The present invention relates to surgical instruments for operating on joints and, more particularly, to novel hook-cutter and grasper-cutter for arthroscopic endodissections and to a method of repairing meniscus injuries using these and/or other cutters.
Many surgical operations, for example, arthroscopic procedures and the like, require the surgeon to resect (i.e., cut and remove) small pieces of tissue from the body of the patient. Even though these pieces may be very tiny, it may be important that they not be dropped or otherwise mislaid, so as to remain within the body cavity after the operation.
For example, even small pieces of tissue can cause significant discomfort and pain if left within the interstices of human joints, where they may interfere with the healing and proper functioning of the joint, perhaps even causing further deterioration thereof. Alternatively, the procedure may involve a biopsy, wherein retaining the small piece may be critical for further diagnosis and treatment.
Furthermore, it is often important to accomplish surgical procedures in as quick, efficient and reliable a manner as is possible. Delay or error can result in complicating or serious consequences. While clamping the tissue with a pair of forceps (surgical pliers, graspers) and thereafter amputating it with a scalpel or the like may be crudely effective, this involves two separate instruments and a cumbersome and time-consuming series of operations. In some cases, there may not be enough room for both instruments, for example, within the interior of a human or animal joint.
Surgical instruments which save time and which free the hands of the surgeon for other functions can be of great aid in achieving successful surgery.
Under these guidelines, U.S. Pat. No. 5,254,129 to Alexander teaches a grasper-cutter, referred to therein as a resector. The resector instrument of Alexander has a set of opposed jaws that pivot about a common axis with respect to a shaft of the instrument's handle. The upper jaw has an upper blade rigidly affixed to one side thereof. A lower blade is rigidly affixed to the shaft. When the upper jaw and upper blade are jointly forced to pivot downward by a push rod on the shaft, the rotating upper blade moves past the stationary lower blade to amputate a piece of tissue in scissors-cutting fashion. The lower jaw is simultaneously forced (by the interposed tissue) to rotate about its pivot downwardly, i.e., in the same direction as and in fixed tandem with the upper jaw. The lower jaw is held tightly against the interposed tissue via a stiff spring against which the lower jaw is biased. The spring causes the jaws to tightly clasp the tissue in plier-clamping fashion during and after its amputation from its attachment. The instrument is operated by a scissors handle arrangement.
The instrument by Alexander suffers several limitations which, as is further detailed hereinunder, are addressed by the grasper-cutter of the present invention.
First, the blades of the instrument by Alexander are arranged and operated in a fashion similar to scissors. As such, at any given time point, the blades contact and act on a lengthy part of the dissected tissue, which requires greeter amount of force as compared with, for example, an instrument having blades designed to operate at a singular tissue point at a time.
Second, the jaws operating spring mechanism disclosed by Alexander is highly prone to being stuck and inoperative due to tissue debris which can accumulate within the mechanism. In this case both the cutting and the grasping functions are eliminated.
Third, since the operation of the jaws and the blades depend on the spring mechanism, cutting and grasping using the instrument by Alexander are progressed simultaneously. This design does not ensure positive grasping before cutting. As a result, in some cases, cutting may be completed prior to full grasping, which may lead to a loss of the dissected tissue part within the cavity of the organ or body part under operation.
Related art is further disclosed in U.S. Pat. Nos. 5,443,575, and 5,531,756, both teach cutters but fail to teach a grasper combined therewith, and U.S. Pat. No. 4,662,371, which teaches a grasper, yet fails to teach a cutter combined therewith.
U.S. Pat. No. 5,549,623 to Sharpe et al., and U.S. Pat. Nos. 5,385,570 and 5,582,618 to Chin et al., all teach hook-cutters, which are referred to therein as surgical cutting instruments. These instruments featuring a surgeon operable control handle for advancing a blade over a fenestrated hook so that tissue within said fenestrated window area is dissected. In both cases, the blade is translatable along a side of the hook. The limitation of these instrument is in the relation between the hook and the blade. Since the blade translates along one side of the hook, it is likely that tissue debris will stuck between the blade and the hook, to thereby separate the blade from the side of the hook and render the blade inoperative.
Related art is further disclosed in U.S. Pat. No. 4,444,184, which teaches a cutter yet fails to teach a hook; and U.S. Pat. No. 4,443,474, which teaches a hook, yet fails to teach a cutter.
FIG. 1 describes steps undertaken during a prior art knee surgery, while repairing a "bucket handle" tear injury of the meniscus. Thus, in order to remove the tear, while holding the handle with a surgical grasper, a partial cut is first made in the posterior end of the torn tissue, as is indicated by arrow 20, such that a narrow posterior link connects the torn tissue to the posterior end of the meniscus. Then, a complete cut is made in the anterior end of the torn tissue, as is indicated by arrow 22, to thereby dissociate that end from the anterior part of the meniscus. Thereafter, the anterior free end of the torn tissue is grasped with the surgical grasper, and while twisting the grasper and therefore the torn tissue, the torn tissue is detached from the meniscus at the posterior link and is removed from the knee cavity.
This prior art method suffers two major limitations. First it calls for three portals to be formed in the knee of the patient, i.e., a portal for the cutter, a portal for the grasper and a third portal for an arthroscope which is used for lighting, imaging, washing and application of suction at the knee cavity. Second the procedure is lengthy, because each tool is used to perform a single action, i.e., the cutter only cuts and therefore the surgeon is in need for a grasper to be present and simultaneously operated. In addition, the cutter and grasper need to be relocated for each of the posterior and anterior cuts described above.
There is thus a widely recognized need for, and it would be highly advantageous to have, hook-cutter and grasper-cutter devoid of the above limitations associated with prior art equivalent instruments, which are used, according to the present invention, for repairing meniscus injuries, such as a bucket handle tear injury faster while restricting the number of portals formed in the operated knee to two portals.